This review describes exciton diffusion simulation strategies in condensed phase organic semiconductors. Methods for calculating energy transfer rate constants are discussed along with procedures for how to account for energetic disorder. Exciton diffusion can be modelled by using kinetic Monte-Carlo methods or master equations. Recent literature on simulation efforts for estimating exciton diffusion lengths of various conjugated polymers and small molecules is introduced. These studies are discussed in the context of the effects of morphology on exciton diffusion and the necessity of accurate treatment of disorder to accurately reproduce experimental results.